[PATCH] EXT2: Remove superblock lock contention in ext2_statfs
Fix a performance degradation introduced in 2.6.17. (30% degradation
running dbench with 16 threads)
Commit 21730eed11de42f22afcbd43f450a1872a0b5ea1, which claims to make
EXT2_DEBUG work again, moves the taking of the kernel lock out of
debug-only code in ext2_count_free_inodes and ext2_count_free_blocks and
into ext2_statfs.
The same problem was fixed in ext3 by removing the lock completely (commit
5b11687924e40790deb0d5f959247ade82196665)
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index d487043..b1981d0 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -539,7 +539,6 @@
#endif /* EXT2FS_DEBUG */
-/* Superblock must be locked */
unsigned long ext2_count_free_blocks (struct super_block * sb)
{
struct ext2_group_desc * desc;
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index de85c61..695f69c 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -637,7 +637,6 @@
return ERR_PTR(err);
}
-/* Superblock must be locked */
unsigned long ext2_count_free_inodes (struct super_block * sb)
{
struct ext2_group_desc *desc;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index ca5bfb6..4286ff6 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1083,7 +1083,6 @@
unsigned long overhead;
int i;
- lock_super(sb);
if (test_opt (sb, MINIX_DF))
overhead = 0;
else {
@@ -1124,7 +1123,6 @@
buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
buf->f_ffree = ext2_count_free_inodes (sb);
buf->f_namelen = EXT2_NAME_LEN;
- unlock_super(sb);
return 0;
}
